Cryptology ePrint Archive: Report 2014/174

Analysis of a Modified RC4 Algorithm

T.D.B Weerasinghe

Abstract: In this paper, analysis of a simply modified RC4 algorithm is presented. RC4 is the most widely used stream cipher and it is not considered as a cipher that is strong in security. Many alternatives have been proposed to improve RC4 key generation and pseudo random number generation but the thoughts behind this work is to try out a simple modification of RC4ís PRGA, where we can mention like this:
Output = M XOR GeneratedKey XOR j
After having done the modification the modified algorithm is tested for its secrecy and performance and analyzed over the variable key length with respect to those of the original RC4. The results show that the modified algorithm is better than the original RC4 in the aspects of secrecy and performance.